Almost five years ago, Sainsbury's supermarkets started giving you vouchers to the value of how much cheaper your shopping might have been elsewhere. That's a win for the consumer, right? Not even remotely, says Dan.

Last month, Dan attended the EEBO-TCP hackathon, and worked alongside humanities researchers to collaborate on software that extracted previously unexplored data out of 25,000 recently-digitised 15th-17th century texts.

When using the Squiz CMS, Dan noticed that his CAPTCHA kept containing the same patterns of letters. These turned out to be the names of early developers on the system, which in turn lead Dan to uncover Easter Eggs in the software that have been deliberately concealed by their authors.